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PMP20330: Isolated power supply + isolated rs485

Rustem Avkhadiev
Genius 3550 points
Part Number: PMP20330
Other Parts Discussed in Thread: CC1310, , ISO15, PMP, CC3200, TIDA-00486

Hello!

My board (based on cc1310) will work as a radio-bridge between Industrial machine and Concentrator.

It's connected to machine by rs485 and powered by 24V DC from the same machine. I need isolation for both power supply and communication.

I found ref. design TIDUA49C, that is very close to my goal, but it have very complicated and expensive power supply part because of AC support.

I'm going to combine RS485 part from TIDUA49C and Power part from PMP20330.

1. Can i use GND_Sec1/5Vout (PMP20330) as power supply for GND2/VCC2    ISO15DW (TIDUA49C), and, in the same time, GND_Sec2/3P3Vout (PMP20330) as power supply for GND1/VCC1    ISO15DW (TIDUA49C) and my cc1310? Or i need additional power supply for isolated part of my board? Is Vout1 and Vout2 isolated from each other?

2. How can i expand Vin range from 18V-31V to 5V-31V?

 

Any advices for effective solution are welcome!

  • 0
    TI__Prodigy 290 points

    Rustem,

    Vout1 and Vout2 are somewhat isolated from eachother. How much isolation do you need between the two supplies? The ISO15 provides 4kV of isolation, but I am unsure on how much isolation there is between the the secondary windings of the transformer in the PMP20330 design. (I have contacted the designer).

    One option would be to use a single winding transformer instead and then use the output of the LM156Q for the non-isolated side of the circuit, unless you need the 7.5V output as well.

    I am also asking the PMP designer about extending the voltage range, what voltage do you need for the output of Vout_Pri?

  • 0 in reply to Jarrod Krebs
    Genius 3550 points
    Jarrod, thank you for a quick answer!

    1. Actually I'm new to industrial design, so i don't know the exact value of isolation needed. 4kV sounds very good.
    2. It's a good idea to use Vout_Pri for a non-isolated side, but maximum value of ISO15 VDD2 is 6V, 7.5V will be too much.
    3. For isolated part (cc1310) i need 3.3V, 0.5 A
  • 0 in reply to Rustem Avkhadiev
    TI__Prodigy 290 points
    According the PMP20330 designer the 5V Vin will be difficult with current topology, you probably want to look for a Flybuck-boost topology. However, PMP20210 may be an option if you only need the 3.3V isolated supply. It is 12V to 56Vin, 3.3V @0.6A.

    I guess I am confused on what power rails you need and which need to be isolated.
    From what I can tell you could get away with just a 3.3V isolated and a non-isolated 3.3V supply for the ISO15 and CC3200. The CC1310 would be on the Isolated 3.3V

    Yet another option would be to use 2 separate transformers in place of T1 on the PMP20330 design to isolate the 5V and 3.3V rails.

    What power part is too expensive? The PMP20330 has a more expensive power part than the TIDA-00486 (TIDUA49C).
  • 0 in reply to Jarrod Krebs
    Genius 3550 points
    I need isolated power supply for GND1/VCC1 ISO15 and cc1310 (3.3 V).
    Also i need power supply for GND2/VCC2 ISO15 (3.3 V or 5V), it's can be non-isolated.

    You right, PMP20330 is more expensive, but TIDA-00486 has a huge capacitor (EEV-FK1K331M) which will greatly increase the height of my board.